thx !I'm 99% sure I took mine out and left it out and it worked fine. They are kinda tricky to get apart so if you already have it open, might as well take it out. The only thing it does is keep time - and if you have it on the network it'll sync with NTP for time anyways. Batteries will eventually leak, so my vote is out.
All G4 Macs will work if you remove the PRAM battery, just the date and some other settings won't save properly but it should be fine for the most part....does the iMac G4 still work if you remove the battery (to be on the safe side) ?